Secure integrated circuit cards, commonly referred to as smart cards, may be of the form of an embedded integrated circuit hardware device that is small enough to fit into a user's pocket. Secure integrated circuit cards can be used in many situations where critical information must be stored and shared. For example, set-top boxes that facilitate pay-per-view or video-on-demand features can use a secure integrated circuit card to supply user account information to a provider along with a request for access to such features, and to subsequently decrypt encrypted digital video streams that may be provided in response to the request. As another example, a Subscriber Identity Module (SIM) card in a Global Systems for Mobile Communications (GSM) phone can be used to store a user's personal information, such as his or her phone book, device preferences, preferred network(s), saved text or voice messages and service provider information. A SIM card can allow a user, for example, to change handsets while retaining all of his or her information on the SIM card. Smart cards can be used in a variety of applications (e.g., electronic payment systems, including specialized auto-debit devices such as public transportation cards and personal identification documents, such as passports, drivers licenses, and medical identification cards).
Because of the potential value of protected data stored in a smart card, hackers may employ various techniques to access or corrupt the protected data. For example, a hacker may grind off a portion of the smart card packaging in order to access internal signals and bypass security measures that may be in place. As another example, a hacker may subject the smart card to various kinds of radiation (e.g., laser light directed to exposed internal circuits or x-ray or gamma radiation directed through packaging) in an attempt to corrupt protected data. In some implementations, corruption of protected data at certain locations in the device can cause the device to bypass security measures (e.g., encryption algorithms) or to yield information to the hacker regarding device architecture or the protected data itself.